Tubular sets are commonly used for conveying blood between a patient and extracorporeal blood treatment apparatus such as dialyzers, blood oxygenators, and similar devices. In the setup of these devices, they must be initially filled with a physiological solution such as normal saline solution before blood is introduced into the sets and extracorporeal treatment apparatus.
Separate or attached priming sets are used in the prior art to deliver such solutions to the fluid pathways of extracorporeal tube sets and the blood processing devices before, during, and after a medical procedure such as hemodialysis. Before the procedure, saline solution must be used to prime the set's fluid pathway, displacing all air. During dialysis, saline solution may have to be rapidly added via the set if the patient suffers hypotension. Also, saline solution may be used as a diluent in drug administration which is directly infused into the extracorporeal blood pathway. Then, at the end of dialysis, saline solution is added to the set to displace all blood back to the patient.
Priming sets are basically simplified versions of the conventional i.v. administration sets used in infusion therapy.
A dialysis se t comprises a tubular structure having one end connected to a patient connector and the other end connected to the extracorporeal treatment device. Arterial dialysis sets receive blood from the patient and convey it to the extracorporeal device. Venous sets receive blood from the extracorporeal device and convey it back to the patient.
Such a prior art dialysis extracorporeal treatment system comprises an arterial set and a venous set, both of which are connected to a dialyzer. The arterial set also carries a branching tube, called a saline administration branch line, typically terminating with a luer lock connector for connection with an end of the priming set. Thus, the priming set connects with the saline administration branch line of the arterial set, and saline solution may pass in one step upstream in the arterial set to the patient connector end, to fill that area. Then, in another step, clamps are closed and opened to allow saline to pass downstream through the rest of the set, to prime the rest of the entire system.
As another option in the prior art, the priming set, reversibly connected to a bag of physiological solution, is directly connected to the patient connector of the arterial set. Then, the saline can flow in a single step through the entire system of the arterial set, the dialyzer, and the venous set, to prime it. Following this, one must disconnect the patient connector and priming set, and connect the connector of the priming set to the saline administration branch line, since saline solution will be subsequently needed during the dialysis process.
Since connection of the patient connector with the patient is essentially the last step to be performed after priming and before the initiation of the hemodialysis, the wet patient connector in this circumstance may lie around in an exposed manner, waiting for the final priming steps to be performed, particularly the connection of the priming set to the saline administration branch line, and other final steps. This is undesirable, since it leaves the patient connector both wet from its prior connection, and exposed to the air, which invites contamination.
Also, in the prior art, the use of a separate, separable priming set is generally required to enable the multiple connections and disconnections which are commonly used. However, this causes extra expense in connectors, clamps, sterility protectors, and assembly and packaging.
Further in the prior art, a branching injection site is generally provided to the priming set, which becomes a way that drugs and supplemental fluids may be administered to the system. However, an injection site uses a hypodermic needle to obtain connection through it. The flow through such a needle, and also through valved ports, blunt, hollow probes, and the like used as substitutes for needles, is low because needles and the like are constricted, and thus have low flow rates. The flow is particularly not sufficient for high flow needs such as hypotensive fluid replacement or efficient priming/rinse back of the blood line set. Likewise, valved ports have this disadvantage, and also they are much more expensive than injection sites and needles.
Also, in the circumstance where priming is performed directly through the saline administration branch lines of conventional arterial sets, the retrograde flow of fluid back to the arterial patient connector adds time-consuming connections and clamping.
By this invention, a simplification of the priming process is achieved. The system may be primed in a single step from the patient connector, which is advantageous, and the patient connector may simultaneously be protected from contamination until it is fully time to switch the patient connector to engage the blood system of the patient, to effect the extracorporeal blood treatment process. Where in the prior art two connections after priming must be made, one with the patient connector, and the other with the priming set connector and the saline administration branch line of the set, only one connection after priming has to be made in this invention, that of the patient connector. Also, an extra connector becomes available in accordance with this invention which is a higher flow luer connector, rather than a restricted flow needle or an expensive substitute, so that in the event of the urgent need for high flow fluid administration into the set the access is available.